The federal budget will be about $5 billion a year better off and moving faster to surplus if Treasury adopts similarly bullish forecasts to the Reserve Bank of Australia's more rosy outlook for the economy.

Treasurer John Frydenberg celebrated the RBA's upbeat outlook for economic growth and employment after meeting the central bank's board members.

Though Treasury forecasts growth over the financial year and the central bank estimates are for the calendar year, the government's two premier economic institutions tend to closely converge on their outlook numbers.

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"Other things equal, that would improve the budget bottom line by about $5 billion a year," Mr Richardson said.

The May budget forecast an underlying cash deficit of $14.5 billion this fiscal year and a small positive balance of $2.2 billion for 2019-20.

Treasury forecast year average real (inflation-adjusted) GDP growth of 2¾ per cent in 2018-19 and 3 per cent in 2019-20.

Nominal GDP, which is not adjusted for inflation, is the key to determining budget taxation revenue and the RBA does not typically forecast this parameter.

"The good news there is in profits – especially in coal - but there's bad news in wages," Mr Richardson said.

Government sources have repeatedly downplayed the prospect of a surplus this fiscal year, but private sector budget experts are growing more optimistic the bottom line could be slightly in the black in 2018-19, a year ahead of the government's latest forecast.

The government will update its budget forecasts in mid-December soon after the September quarter national accounts are published.

Outlook Economics director Peter Downes, a former senior Treasury forecaster, said the budget was looking "pretty good" and a small surplus this fiscal year was possible.

"If commodity prices hold up, mining profits remain high and the currency stays down, the budget could be in surplus for 2018-19," he said.

"There is some good luck, but you have to give the government credit for doing a lot of work in exercising fiscal restraint by restraining welfare expenditure while providing room for the NDIS [National Disability Insurance Scheme] to roll out."

The government has recently committed new medium-to-long term spending of $9 billion in extra GST for the states, $4.5 billion for Catholic and Independent schools and $3.6 billion to bring forward tax cuts for small and medium enterprise companies. The government has vowed to inject an initial $3.9 billion into a future drought fund, with the money being allocated from the Building Australia Fund.

"There will be a temptation for the government to be spending money for the election, but quite often the spending commitments are for the next financial year," Mr Downes said.